Rolls 1 and 2, whose axes make a small angle, are driven from shaft A through meshing gears 3 and 4. The strip of stock 5 is subject to varying pressure as it passes through the rolls. The left edge is subject to more strain than the right edge. This forms the straight strip into a helical ribbon. The angle between the rolls is adjusted by screws 6 which turn yoke 7 about fixed axis B. Pressure is applied to the top roll by springs 8 whose tension can be varied by nuts. The diameter of the helix is maintained constant by guide 9.
$2974$CxG,FD$